ISO/TS 4869-5:2006
(Main)Acoustics — Hearing protectors — Part 5: Method for estimation of noise reduction using fitting by inexperienced test subjects
Acoustics — Hearing protectors — Part 5: Method for estimation of noise reduction using fitting by inexperienced test subjects
ISO/TS 4869-5:2006 specifies a method for measuring noise reduction of passive hearing protectors at the threshold of hearing. The method is designed to provide estimates of the noise reduction obtained by typical groups of users in real-world occupational settings, who may lack the training and motivation to wear hearing protectors in an optimum manner. The principle of the test method is to measure the difference in hearing threshold with and without wearing a hearing protector. This difference between the thresholds constitutes the noise reduction. The measurement is done twice on a given number of test subjects. This test method yields data that are collected at low sound pressure levels (close to the threshold of hearing), but which are also representative of the noise reduction values of hearing protectors at higher sound pressure levels. ISO/TS 4869-5:2006 is inapplicable for level-dependent hearing protectors for sound pressure levels above the point at which their level-dependent characteristics become effective.
Acoustique — Protecteurs individuels contre le bruit — Partie 5: Méthode d'estimation de la réduction du bruit au moyen de réglages par des sujets d'essai non expérimentés
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TECHNICAL ISO/TS
SPECIFICATION 4869-5
First edition
2006-10-15
Acoustics — Hearing protectors —
Part 5:
Method for estimation of noise reduction
using fitting by inexperienced test
subjects
Acoustique — Protecteurs individuels contre le bruit —
Partie 5: Méthode d'estimation de la réduction du bruit au moyen de
réglages par des sujets d'essai non expérimentés
Reference number
©
ISO 2006
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ii © ISO 2006 – All rights reserved
Contents Page
Foreword. v
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Measurement of the noise reduction of hearing protectors . 3
4.1 Test signals . 3
4.2 Test site . 3
4.2.1 Conditions to be met for the test to be valid . 3
4.2.2 Reverberation time . 4
4.2.3 Background noise. 4
4.3 Test equipment . 5
5 Test subjects . 6
5.1 Conditions for subject acceptance/dismissal . 6
5.1.1 General. 6
5.1.2 Age and sex. 6
5.1.3 Previous experience with hearing protectors. 7
5.1.4 Anatomical features. 7
5.1.5 Maximum hearing threshold levels. 7
5.1.6 Minimum hearing threshold levels. 7
5.1.7 Literacy . 7
5.1.8 Threshold variability. 7
5.2 Number of subjects . 7
5.3 Otoscopic inspection . 8
5.4 Spectacles and jewellery . 8
5.5 Maximum number of tests per subject. 8
5.6 Exceptions. 8
6 Product samples. 8
6.1 General. 8
6.2 Custom-moulded ear-plugs . 8
6.3 Special requirements for product instruction . 8
6.4 Variable position headbands. 9
6.5 Variable band force. 9
7 Test procedure . 9
7.1 Number of open-ear and occluded-ear threshold measurements. 9
7.2 Information to subjects . 9
7.3 Prior to entering the test room . 10
7.4 Inside the test room. 10
7.4.1 Positioning the subject . 10
7.4.2 Quiet period prior to first threshold determination. 11
7.4.3 Fitting the hearing protector for test . 11
7.4.4 Re-determination of thresholds . 11
8 Computation of noise reduction values .12
8.1 General. 12
8.2 Calculation of the individual noise reductions. 12
8.3 Calculation of group noise reduction. 12
8.4 Uncertainty of the noise reduction data. 13
9 Reporting of data . 13
Annex A (informative) Uncertainty of hearing protector noise reduction measurements. 15
Bibliography . 18
iv © ISO 2006 – All rights reserved
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
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International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of normative document:
⎯ an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
⎯ an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting
a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is
confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an
International Standard or be withdrawn.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TS 4869-5 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
ISO/TS 4869 consists of the following parts, under the general title Acoustics — Hearing protectors:
⎯ Part 1: Subjective method for the measurement of sound attenuation
⎯ Part 2: Estimation of effective A-weighted sound pressure levels when hearing protectors are worn
1)
⎯ Part 3 : Measurement of insertion loss of ear-muff type protectors using an acoustic test fixture
⎯ Part 4: Measurement of effective sound pressure levels for level-dependent sound-restoration ear-muffs
(ISO/TR)
⎯ Part 5: Method for estimation of noise reduction using fitting by inexperienced test subjects (ISO/TS)
1) To be published.
The following part is under development:
2)
⎯ Part 6: Active noise reduction of hearing protectors
Annex A of this part of ISO 4869 is for information only.
2) Presently a preliminary work item.
vi © ISO 2006 – All rights reserved
Introduction
Hearing protectors are used to reduce the noise to which the ear is exposed. Hearing protectors are generally
divided into ear-muffs and ear-plugs with a great variety of products within both categories. The measurement
conditions given in this Technical Specification – making use of inexperienced hearing protector users – is
believed to provide results that are representative for the noise reduction obtained by groups of typical users
in real-world occupational settings.
The method described in ISO 4869-1 yields the sound attenuation of the hearing protector under test. The
result of the measurement is a pure physical characteristic of the hearing protector.
The method described in this Technical Specification yields the performance of the system as a whole, i.e.
hearing protector, test subjects, fitting and instruction.
TECHNICAL SPECIFICATION ISO/TS 4869-5:2006(E)
Acoustics — Hearing protectors —
Part 5:
Method for estimation of noise reduction using fitting
by inexperienced test subjects
1 Scope
This Technical Specification specifies a method for measuring noise reduction of passive hearing protectors at
the threshold of hearing. The method is designed to provide estimates of the noise reduction obtained by
typical groups of users in real-world occupational settings, who may lack the training and motivation to wear
hearing protectors in an optimum manner.
The principle of the test method is to measure the difference in hearing threshold with and without wearing a
hearing protector. This difference between the thre
...
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